Effect of interleukin-17 on the expression of chemokines in gingival epithelial cells

The role of interleukin (IL)-17 in cellular communication in inflammation has been well described, and a positive correlation between the severity of periodontitis and the level of IL-17 was reported. Although epithelial cells are a major target of IL-17, little is known about the effect of IL-17 on the production of chemokines by human gingival epithelial cells (HGECs). We evaluated the effects of IL-17 on the expression of CXCL8 and CCL2 by HGECs using quantitative real-time PCR and ELISA. In addition, the role of the nuclear factor (NF)-κB signalling pathway in the IL-17-mediated expression of chemokines was assessed using a specific inhibitor. Stimulation with IL-17 up-regulated the expression of CXCL8 mRNA but not of CCL2 mRNA in HGECs, whereas tumour necrosis factor-α (TNF-α) elevated the expression of mRNA for both chemokines. Stimulation with IL-17 up-regulated the secretion of CXCL8 protein, but not the secretion of CCL2 protein. The effect of IL-17 on CXCL8 production was suppressed using an anti-IL-17R Ig, suggesting a role for a specific receptor-ligand interaction. Inhibition of the NF-κB signalling pathway demonstrated that NF-κB activation is required for the CXCL8 expression in HGECs. In conclusion, IL-17 is involved in the regulation of the innate immune response in HGECs by inducing CXCL8 production.